The moisture susceptibility of asphalt containing alumina trihydrate (ATH) was assessed through the surface free energy. Physical properties and flame retardancy of ATH samples were also investigated. For research purposes SBS modified asphalt samples with different dosages (0-14 %) of ATH were prepared. Increased viscosity, softening point limiting oxygen index and lower penetration ductility, were investigated for the ATH modified samples. ATH has a significant negative effect on the moisture-induced damage potential of asphalt mixture from the view of micromechanisms.